Conventional color printers are subject to color drift requiring recalibration of the color rendering process. One cause of such drift is deviation of the underlying components due to age or changes in the environment.
For example, a typical color printing device may vary due to changes in the underlying marking process in response to external conditions. These variations from a known, standard state can result in undesirable variation in the appearance of the output from the color printing device.
Conventionally, a color reprographic device is periodically recalibrated to maintain it in a known state by using a scanner as a colorimeter. The reprographic device creates a color target (conventionally a set of color patches) to be printed by the color reprographic device. By scanning the printed color target and passing the scanned image through a calibration conversion table, a set of color measurements are obtained which can be used to derive a set of curves, which can be used to modify the output characteristics of the device to compensate for drifts.
An example of such a conventional calibration process is disclosed in U.S. Pat. No. 7,319,545. The entire content of U.S. Pat. No. 7,319,545 is hereby incorporated by reference.
The various conventional calibration processes were based upon the color target being printed on a standard recording media (paper). Thus, the accuracy of the calibration process could be negatively impacted if a non-standard recording media is utilized for the rendering of the color target because the brightness (whiteness) of the recording media (paper) can affect the measured values of the color target.
Therefore, it is desirable to provide a calibration process that compensates for the use of a non-standard recording media for the rendering of the test target.